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256 lines
5.6 KiB
C
256 lines
5.6 KiB
C
/* vi:set ts=4:
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*
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* mdev - Mini udev for busybox
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*
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* Copyright 2005 Rob Landley <rob@landley.net>
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* Copyright 2005 Frank Sorenson <frank@tuxrocks.com>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
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*/
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#include <ctype.h>
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#include <dirent.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <sys/sysmacros.h>
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#include <sys/types.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include "busybox.h"
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#include "xregex.h"
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#define DEV_PATH "/dev"
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#define MDEV_CONF "/etc/mdev.conf"
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#include <busybox.h>
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int root_major, root_minor;
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/* mknod in /dev based on a path like "/sys/block/hda/hda1" */
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static void make_device(char *path)
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{
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char *device_name, *s;
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int major, minor, type, len, fd;
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int mode = 0660;
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uid_t uid = 0;
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gid_t gid = 0;
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RESERVE_CONFIG_BUFFER(temp, PATH_MAX);
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/* Try to read major/minor string */
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snprintf(temp, PATH_MAX, "%s/dev", path);
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fd = open(temp, O_RDONLY);
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len = read(fd, temp, PATH_MAX-1);
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close(fd);
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if (len < 1) goto end;
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/* Determine device name, type, major and minor */
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device_name = strrchr(path, '/') + 1;
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type = strncmp(path+5, "block/", 6) ? S_IFCHR : S_IFBLK;
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if (sscanf(temp, "%d:%d", &major, &minor) != 2)
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goto end;
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/* If we have a config file, look up permissions for this device */
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if (ENABLE_FEATURE_MDEV_CONF) {
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char *conf, *pos, *end;
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/* mmap the config file */
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if (-1 != (fd=open(MDEV_CONF,O_RDONLY))) {
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len = lseek(fd, 0, SEEK_END);
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conf = mmap(NULL, len, PROT_READ, MAP_PRIVATE, fd, 0);
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if (conf) {
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int line = 0;
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/* Loop through lines in mmaped file*/
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for (pos=conf; pos-conf<len;) {
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int field;
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char *end2;
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line++;
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/* find end of this line */
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for(end=pos; end-conf<len && *end!='\n'; end++)
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;
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/* Three fields: regex, uid:gid, mode */
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for (field=3; field; field--) {
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/* Skip whitespace */
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while (pos<end && isspace(*pos))
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pos++;
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if (pos==end || *pos=='#')
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break;
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for (end2=pos; end2<end && !isspace(*end2) && *end2!='#'; end2++)
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;
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switch (field) {
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/* Regex to match this device */
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case 3:
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{
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char *regex = strndupa(pos,end2-pos);
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regex_t match;
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regmatch_t off;
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int result;
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/* Is this it? */
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xregcomp(&match,regex,REG_EXTENDED);
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result = regexec(&match,device_name,1,&off,0);
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regfree(&match);
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/* If not this device, skip rest of line */
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if (result || off.rm_so || off.rm_eo!=strlen(device_name))
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goto end_line;
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break;
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}
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/* uid:gid */
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case 2:
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{
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char *s2;
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/* Find : */
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for(s=pos; s<end2 && *s!=':'; s++)
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;
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if (s == end2)
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goto end_line;
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/* Parse UID */
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uid = strtoul(pos,&s2,10);
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if (s != s2) {
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struct passwd *pass;
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pass = getpwnam(strndupa(pos,s-pos));
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if (!pass)
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goto end_line;
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uid = pass->pw_uid;
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}
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s++;
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/* parse GID */
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gid = strtoul(s,&s2,10);
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if (end2 != s2) {
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struct group *grp;
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grp = getgrnam(strndupa(s,end2-s));
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if (!grp)
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goto end_line;
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gid = grp->gr_gid;
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}
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break;
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}
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/* mode */
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case 1:
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{
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mode = strtoul(pos,&pos,8);
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if (pos != end2)
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goto end_line;
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else
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goto found_device;
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}
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}
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pos = end2;
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}
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end_line:
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/* Did everything parse happily? */
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if (field && field!=3)
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bb_error_msg_and_die("Bad line %d",line);
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/* Next line */
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pos = ++end;
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}
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found_device:
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munmap(conf, len);
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}
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close(fd);
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}
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}
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sprintf(temp, "%s/%s", DEV_PATH, device_name);
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umask(0);
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if (mknod(temp, mode | type, makedev(major, minor)) && errno != EEXIST)
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bb_perror_msg_and_die("mknod %s failed", temp);
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if (major==root_major && minor==root_minor)
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symlink(temp,DEV_PATH "/root");
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if (ENABLE_FEATURE_MDEV_CONF) chown(temp,uid,gid);
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end:
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RELEASE_CONFIG_BUFFER(temp);
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}
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/* Recursive search of /sys/block or /sys/class. path must be a writeable
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* buffer of size PATH_MAX containing the directory string to start at. */
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static void find_dev(char *path)
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{
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DIR *dir;
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size_t len = strlen(path);
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struct dirent *entry;
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if ((dir = opendir(path)) == NULL)
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return;
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while ((entry = readdir(dir)) != NULL) {
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/* Skip "." and ".." (also skips hidden files, which is ok) */
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if (entry->d_name[0] == '.')
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continue;
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if (entry->d_type == DT_DIR) {
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snprintf(path+len, PATH_MAX-len, "/%s", entry->d_name);
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find_dev(path);
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path[len] = 0;
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}
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/* If there's a dev entry, mknod it */
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if (!strcmp(entry->d_name, "dev")) make_device(path);
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}
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closedir(dir);
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}
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int mdev_main(int argc, char *argv[])
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{
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char *action;
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char *env_path;
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RESERVE_CONFIG_BUFFER(temp,PATH_MAX);
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/* Scan */
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if (argc == 2 && !strcmp(argv[1],"-s")) {
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struct stat st;
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stat("/", &st); // If this fails, we have bigger problems.
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root_major=major(st.st_dev);
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root_minor=minor(st.st_dev);
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strcpy(temp,"/sys/block");
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find_dev(temp);
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strcpy(temp,"/sys/class");
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find_dev(temp);
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/* Hotplug */
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} else {
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action = getenv("ACTION");
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env_path = getenv("DEVPATH");
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if (!action || !env_path)
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bb_show_usage();
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if (!strcmp(action, "add")) {
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sprintf(temp, "/sys%s", env_path);
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make_device(temp);
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} else if (!strcmp(action, "remove")) {
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sprintf(temp, "%s/%s", DEV_PATH, strrchr(env_path, '/') + 1);
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unlink(temp);
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}
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}
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if (ENABLE_FEATURE_CLEAN_UP) RELEASE_CONFIG_BUFFER(temp);
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return 0;
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}
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